1. Field of the Invention
The invention relates generally to implantable medical devices and, more particularly, to implantable sensors having a biocompatible coating that controls the growth of tissue, or inhibits the growth of tissue, over and around the sensor.
2. Description of Related Art
Human implantable sensors may be used to gather important information about the body's internal environment on a regular basis. Pressure inside an artery, fluid flow inside an artery, body temperature, posture sensing and monitoring of chemical changes are among the different types of information that could be gathered by an implantable sensor.
A problem exists in that any sensor that is implanted into living tissue is subject to tissue growth over and around it. Some tissue growth may be desired in order to embed the sensor and make it a more integral part of the body. However, the sensor's calibration and sensitivity can be adversely effected by different factors of this tissue growth including, but not limited to, the type of tissue that grows over the sensor, the thickness, and the evenness of the tissue growth. For example, in the case of a pressure sensor, the sensitivity of the sensor is affected by the thickness of the tissue while sensor drift is affected by the tension exerted on the sensor by the tissue. This tension, in turn, leads to additional pressure bias that affects the accuracy of the pressure measurements provided by the sensor.
Those skilled in the art have recognized a need for providing a more consistent and predictable growth process in relation to implanted sensors to thereby mitigate the problem of unpredictable tissue growth and its impact on the sensitivity and calibration of sensors. The need for inhibiting tissue growth to further mitigate the foregoing problems has also been recognized. The invention fulfills these needs and others.